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Windowing of Full Wavefield Data in Multiple Domains to Characterize Angle-Beam Shear Wave Scattering (Postprint)
Georgia Institute of Technology Atlanta United States
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Angle-beam ultrasonic inspection methods are frequently based on shear waves since they are readily generated using conventional longitudinal transducers and a wedge. Full wavefield imaging can be employed to measure such waves on the surface of a plate-like specimen after they have scattered from a feature or defect of interest, and multiple shear wave arrivals, or skips, are readily visible due to beam spread 1. Because of the complexity of the total wavefield, which also includes Rayleigh and longitudinal waves, it is challenging to experimentally quantify scattering from the primary skip of interest. Considered here is a methodology to isolate shear wave scattering from a through-hole caused by a specific shear wave skip that is incident upon the hole. First, the residual wavefield is obtained by performing wavefield baseline subtraction before and after the introduction of a scatterer 2. Next, a 3-D Fourier transform is performed to convert the residual signals in the time and space domain t-x-y to the frequency-wavenumber domain omega-kx-ky.
APPROVED FOR PUBLIC RELEASE